Studying the Reflection of an Electromagnetic Wave in Composites Based on a Dielectric Matrix and Particles of Conductor or Semiconductor

Abstract

Based on the formulas derived for the electromagnetic wave reflection coefficient Г at a dielectric loss tangent tanδ from 0 to 100, the dependences of Г are calculated for the dielectric permittivity ε' in the interval 1 ≤ ε' ≤ 100 and tan δ in the interval 0.01 < tan δ <100. The analysis of calculated Г–ε' and Г–tanδ dependences shows that a radical solution to reduce Г is the application of composites with ε' ≤ 10–15. The dielectric characteristics ε', ε'', tan δ, and reflection coefficient Г of existing AlN based composites are analyzed in a frequency band of 12–40 GHz at 16.6–17.9 vol % particles of the conductor Mo and 20 and 40–50 vol % particles of semiconductor SiС. The studied AlN based composites have maximum values of ε' within a frequency range of 12–18 GHz. In this frequency range, the dielectric permittivity ε' = 25–32, the reflection coefficient Г = 0.45–0.49, and tan δ < 0.01 for the composites containing 16.6–17.9 vol % of Mo particles. For the materials containing 40–50 vol % particles of semiconductor SiС, ε' = 18–36, Г = 0.38–0.58, and tan δ < 0.45.